Photographic gelatin hardened with bis isoxazole compounds and their quaternary salts



PHOTOGRAPHIC GELATIN HARDENED WITH BIS ISOXAZOLE COMPOUNDS AND THEIRQUATER- NARY SALTS Donald M. Burness and Jerome J. Looker, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporationof New Jersey No Drawing. Continuation-impart of application Ser. No.486,189, Sept. 9, 1965. This application June 20, 1967, Ser. No. 647,324

Int. Cl. G03c 1/30 US. Cl. 96-111 7 Claims ABSTRACT OF THE DISCLOSUREBis isoxazoles and their quaternary salts are disclosed. The quaternarysalts are particularly useful in rendering carboxyl-containing polymersand other compositions resistant to the swelling from aqueous solutions.

This application is a continuation-in-part of our copending applicationSer. No. 486,189 filed Sept. 9, 1965 now abandoned.

BACKGROUND OF THE INVENTION Field of invention This invention relates toa new class of nitrogen-containing compounds, their ammonium salts, anduses of such materials. In one aspect, this invention relates to therendering of hydrophilic colloid compositions, capable of forminglayers, resistant to the effects of swelling from aqueous solutions.

In another of its aspects, this invention relates to photographicelements comprising a layer hardened by bisisoxazolium salts and havingreduced staining properties.

DESCRIPTION OF THE PRIOR ART The use of gelatin and certain syntheticcarboxyl-containing polymers, alone and in combination with each otheras vehicles in solutions, emulsions, and layers, as for example inphotographic products, is enhanced by increasing their resistance toswelling from aqueous solutions.

Various materials have been suggested for increasing swell resistance ofsuch hydrophilic materials and although some have shown utility, many ofthese have adversely affected the properties, particularly photographicproperties, of materials containing them. In order to improve resistanceto swell or hardening of a hardenable material such as acarboxyl-containing polymer, without adversely affecting photographicmaterials, hardening agents, such as aziridines, have been incorporatedinto the hardenable materials. However, because of their detrimentalphysiological effect, aziridines have not proved wholly satisfactory.

It is evident therefore, that the art would be advanced by an effective,safe, and convenient means for providing good swell resistance tohardenable materials, particularly carboxyl-containing materials, usingcompounds which are readily soluble and which neither adversely affectthe photographic properties of such materials nor adversely affect theindividual workers.

SUMMARY OF INVENTION We have now discovered a new class of hisheterocyclic compounds, as described herein. These compounds comprisetwo isoxazole rings which are linked to one another through carbon atomsat ring positions 2, 4, or of said isoxazole rings where O and N are 1-2with respect to each other. In addition, each isoxazole ring isunsubstituted in the 3 position. Compounds of this type effecnitedStates Patent O tively increase swell resistance from aqueous solutionsof systems comprising a hardenable material, e.g. a carboxylcontainingpolymer, without any significant detrimental side effects.

In practicing this invention, these compounds are conveniently used inthe form of their ammonium salts which are water-soluble and can beeasily incorporated into aqueous compositions comprisingcarboxyl-containing polymers such as gelatin or synthetic polymers.

Such salts can be effectively used in any concentration for hardeningpurposes, although suitable hardening concentrations are generally inthe range of about 1 to about 5 percent, by weight, based on the weightof harden able material such as carboxyl-containing polymer.

As illustrated by Example 11, the hardeners described herein areparticularly effective in color photography since their use results inreducing the stain usually exhibited by multiple layer photographicsilver halide systems which contain a color coupler and hydrophiliccolloid layers. Such layers generally comprise hardenablecarboxyl-containing polymers such as gelatin, vinyl polymers, ormixtures thereof. Suitable carboxyl-containing polymers are film-formingand suitable vinyl polymers are exemplified by ethyl-acrylate-acrylicacid polymer (4:1 by weight), butyl acrylate-acrylic acid polymer (9:1by weight), and the like. The various following examples areillustrative in contrasting the photographic effects of prior arthardening agents in comparison to those agents of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS One embodiment of this inventionrelates to his heterocyclic compounds comprising two isoxazole ringslinked through carbon atoms at ring positions 2, 4, and 5 of saidisoxazole rings, each of said rings being unsubstituted in the 3position.

Another embodiment of this invention relates to a his isoxazole or itsquaternary salt comprising two isoxazole rings unsubstituted in their 3positions and linked at their 2, 4, or 5 positions through a divalentaliphatic or aromatic group.

Another embodiment of this invention relates to bisisoxazolium saltshaving the following formulae:

Ran 9 "nl Z A a" )2 Rs Rn/ t aezea a Rn Rn where each Z is a divalentaliphatic or aromatic radical, each R is aliphatic hydrocarbon of 1-4carbons, each R' is alkyl, cycloalkyl, or aryl, provided R is not linkedto a ring in the 3 position, each n is an integer of from 0 to 2 andeach X is an anion.

Another embodiment relates to a photographic element comprising asupport, and a layer comprised of a carboxyl-containing polymer hardenedwith a bis isoxazolium salt.

Still another embodiment relates to a composition comprising ahydrophilic colloid containing a his isoxazolium salt in hardeningconcentration.

The bis heterocyclic compounds of this invention comprise at least twoheterocyclic rings. The hetero atoms in each of these rings are nitrogenand oxygen in the 1-2 position with respect to each other.

As already indicated, the two isoxazole rings present in theheterocyclic compounds of this invention are linked through carbon atomsat their 2, 4, or 5 positions. Suitable linking groups (designated Z inthe formulae) are divalent aliphatic or aromatic groups. Suitablealiphatic groups, including cycloaliphatic groups, can be straight chainor branched and include alkylene, cycloalkylene, and the like.Generally, a linking group contains not more than carbon atoms andincludes alkylene groups such as tetramethylene, pentamethylene,hexamethylene, and araylene groups, such as phenylene, and the like.Linking groups are preferably hydrocarbon but such groups can alsocontain atoms other than carbon, for example, oxygen, sulfur, nitrogen,and the like. The nitrogen atoms in the two isoxazole rings present inthe compounds of this invention carry aliphatic substituents, designatedas R in the above formulas. Suitable R substituents contain 1-4 carbonatoms and include for example, methyl, ethyl, propyl, butyl, allyl,tertiary butyl, isopropyl, and the like. Each isoxazole ring can carrysubstituents, designated R in the above formulas. Such substituentsoccur at the various available isoxazole ring positions other than 3 andinclude alkyl, cycloalkyl, and aryl groups as exemplified by methyl,ethyl, hexyl, cyclopentyl, cyclohexyl, phenyl, naphthyl, and the like.Such groups can be hydrocarbon or can contain atoms other than carbonand hydrogen, e.g. oxygen or halogen as in hydroxyalkyl or chloroalkylgroups. The anion previously shown as X, can be, for example,perchlorate, p-toluenesulfonate, chloride, nitrate, tetrafiuoroborate,or the like. It is most desirable that the anion contributes to thewater solubility of the base compound and that the entire radicalpossesses a negative valence of two.

A convenient method for preparing the his isoxazole compounds of thisinvention comprises reacting an ap propriate hydroxylamine salt, such ashydroxylamine hydrochloride, and a suitable substance comprising twofl-ketoaldehyde moieties, such asp-phenylenebis(diethylamino-propenone),2,2-phenylenebis-(S-dimethylamino acrolein) and the like, or itsequivalent precursor substance in situ. The novel salts of thesecompounds are prepared by reacting these bis isoxazole compounds withcompounds capable of producing the desired anion in a suitable solvent.All such reactions are carried out in the presence of organic solventsat moderate temperatures. In general, the reaction forming the hisisoxazole compounds is complete in hours or less but may take as long as72 hours and the resulting compounds are isolated by conventionalprocedures. The reactions are not pressure dependent and thereforesuperatmospheric or subatmospheric pressures are employed. As is obviousto one skilled in the art, the specific reaction conditions, forexample, temperature, pressure, and the like, depend upon the particularreactants employed.

The compounds described in this application can be used eifectively incombination with hardenable materials in general but are mostadvantageously used with hydrophilic colloid coating compositions usedin preparing photographic elements added either in solution or asaddition salts. Specific materials which can be hardened according tothe practice of this invention include hardenable carboxyl-containingpolymers such as gelatin, binding materials such as colloidal albumin,water-soluble vinyl polymers, cellulose derivatives, proteins,water-soluble poly acrylamides, dispersed polymerized vinyl compounds,particularly those which increase the dimensional stability ofphotographic materials as exemplified by polymers of alkyl acrylates,methacrylates, acrylic acid, sulfoalkyl acrylates, methacrylates,maleic-acid and the like.

The hardening agents described herein can be used in various kinds ofphotographic emulsions. In addition to being useful in orthochromaticpanchromatic and in frared emulsions, they are also useful in X-ray andother nonoptically sensitized emulsions. They can be added to theemulsions before or after any optically sensitizing dyes which may beused. They are effective in sulfur and gold sensitized silver halideemulsions. Various silver salts can be used as sensitive salts,including, for example, silver bromide, silver iodide, silver chloride,silver chlorobromide silver bromoiodide, or silver chloriodide.

The materials hardened in the practice of this invention can be coatedon a wide variety of supports. Typical supports include those generallyemployed for photographic elements, as exemplified by cellulose nitratefilm, cellulose acetate film, polyvinyl acetal film, polystyrene film,polyethylene terephthalate film, and related film or resinous materialsas well as glass, paper, metal, wood, and the like. Supports such aspaper that are coated with a-olefin polymers, particularly polymers ofa-olefins containing 2-10 carbon atoms, as for example, polyethylene,polypropylene, ethylene butene copolymers, and the like, can also beemployed.

In addition to the hardening agents disclosed herein, photographicemulsions and elements can also contain additional additives,particularly those known to be beneficial in photographic emulsions, asexemplified by optical sensitizers, speed increasing materials, otherhardeners, plasticizers, and the like.

This invention can be further illustrated by the following examples ofpreferred embodiments thereof although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated.

Example 1 .5 ,5 p-phenylene bisisoxazole 3.2 parts of p-diacetylbenzeneand 15 parts of ethyl formate by weight are dissolved in parts ofbenzene. This solution is hten added to a suspension of 6.5 parts ofsodium methoxide in 50 parts of benzene at 10 C. The mixture is allowedto warm to 25 C. and is left standing for 16 hours. The benzene is thendistilled 01f, and the residue dissolved in methanol, and a solution of9.8 parts of dimethylamine hydrochloride in methanol is added. Afterfive hours, the solvent is distilled oif; and the solid residue washedwith benzene and then with water giving 4.2 parts ofl,1'-(p-phenylene)bis-(3-dimethylamino-2- propen-l-one) having a meltingpoint of 260-262 C.

To a suspension of 22 parts of thep-phenylenebis-(dimethylamino-propenone) (the preparation of which isdescribed in the preceding paragraph) in parts of water is added asolution of 12 parts of hydroxylamine hydrochloride in 100 parts ofwater. The mixture is heated on a steam both for 90 minutes; the solidis collected, washed with water, dried and recrystallized fromethanol-chloroform. There is obtained 9.8 parts of 5,5'-(p-phenylene)bisisoxazole which has a melting point of 2152l6 C.

Example 2.-5,5'- (p-phenylene) bis(N-ethylisoxazolium perchlorate) 25parts of triethyloxonium tetrafiuoroborate are dissolved in methylenechloride and to the stirred solution is added a solution of 5 parts of5,5'-(p-phenylene)bis isoxazole (the product of Example 1) in methylenechloride. The mass is allowed to react 20 hours forming 9.8 parts of aproduct having a melting point of 24l-242 C. This product is convertedto the perchlorate with sodium prechlorate forming six parts of 5,5-(p-phenylene)bis(N- ethylisoxazolium perchlorate). The product isrecrystalllzed using as the solvent a mixture of acetonitrile andethanol. The purified material has a melting point of 227 C. at whichtemperature decomposition occurs.

Example 3 .5,5'- (p-phenylene)bis-N-methylisoxazolium methosulfate Amixture of 2.1. parts of 5,5'-(p-phenylene)bis isoxazole and 50 parts ofdimethyl sulfate is heated for one hour on a steam bath. A solidmaterial separate which is washed with ether giving 2.3 parts of5,5'-(p-phenylene) bis(N-methylisoxazolium methosulfate), M.P. l84 C.

Example 4.-5,5'-tetramethylenebis(Z-ethylisoxazolium fluoroborate5,5-tetramethylenebis(isoxazole) is prepared by known methods, as forexample in a process described by A. E. Pohland and W. R. Benson,Chemical Reviews, vol. 66, page 161, 1966, starting with adipylchloride.

A solution of 4 parts of 5,5'-tetramethylenebis(isoxazole) in 50 partsof anhyhrous acetonitrile is treated with 8 parts of triethyloxoniumfiuoroborate. The solution becomes warm and an oil separates, whichcrystallizes on swirling. After 30 minutes, the solid,5,5-tetramethylenebis(2-ethylisoxazolium fiuoroborate) is collected (8parts) and recrystallized from ethanol-acetonitrile to give parts (56percent) of product, with a melting point of 122- 123" C.

Example 5.2,5-dimethylhexane-2,5-diyl-2,2"-bis(5- methylisoxazoliumfluoroborate A mixture of 2.9 parts of 2,5-dimethylhexane-2,5-diol, 3.3parts of S-methylisoxazole, and 7.2 parts of 48 percent fluorobon'c acidis allowed to stand for three days and the solvent is removed. Theresidue is dissolved in acetone (20 parts) and ether is added. The oilthat separates crystallizes on washing with ether and the solidrecrystallizes from acetone, 1.65 parts (18 percent), with a meltingpoint of 130-132 C. A form melting at 126-127 C. and having the correctelemental analysis is also obtained.

Example 6.4,4'-p-phenylenebis(N-ethylisoxazolium fiuoroborate)2,2-p-phenylenebis(l-dimethylamino 1 propen 3- drochloride, .25 part ofconcentrated hydrochloric acid, and 30 parts of acetic acid is heated atrefluex for 3 hours and concentrated. The residue is washed with waterand recrystallized from 20 parts of acetonitrile to give 2.4 parts (57percent) of 4,4-p-phenylenebis(isoxazole). The melting point is 195-196C. The tan color is removed with charcoal.

A hot solution of 2.1 parts of 4,4-p-phenylenebis(isoxazole) in 50 partsof 1,2-dichloroethane is added in one portion to a solution of 10 partsof triethyloxonium fluoroborate in 20 palts of the same solvent. Aftercooling to room temperature, the solid,4,4-p-phenylenebis(N-ethylisoxolium fluoroborate), is collected, 4.4parts (100 percent), M.P. 241 C., decompose. Recrystallization fromacetonitrile gives material melting at 244 C. decompose.

Example 7 As previously indicated, the compounds described herein givevery good results when used as hardeningagents in photographicapplications. To illustrate, the compounds prepared in Examples 2 and 3are added in various concentrations to separate portions of a high-speedgelatino silver bromoiodide photographic emulsion. Each emulsion sampleis coated onto a cellulose acetate film support at a coverage of 459 mg.of silver and 1040 mg. of gelatin per square foot. Each film coating isexposed on an Eastman 1B sensitometer, processed for five minutes inKodak Developer DDK-SO, fixed, washed, and dried. The resistance toswell, relative speed, contrast, and fog are determined and are asfollows:

TABLE 1 1 wk. incubation 120 F., Percentblyl t Fresh test 50% relativehumidity Per e t n Wel based on Re]. R Compound gelatin speed Gamma Fogspeed Gamma Fog DK50 Fix Wash None 100 1.39 .13 69 .94 1 200 Example 2--1 91 1. 2a 14 60 95 3s 1: 300 2%?) 333 Do 3 85 1.22 11 73 97 18 990 460760 D0 6 53 1. 07 08 58 87 09 None 100 1. 23 15 76 1. 13 27 Example3. 3194 1. 27 10 80 1.12 14 D0 74 1. 15 08 71 1.08 09ylidene-N,N-dimethylimmonium perchlorate) is prepared Example 8 fromp-phenylenediacetic acid using the procedure of Z. Arnold, Coll. Czech.Chem. Comm. ,26, 3051 (1961). A

The procedure of Example 7 is repeated using the compounds prepared inExamples 46. The results obmixture of 67 parts of the perchlorate, 500parts of chlorotained are as follows:

TABLE 2 1 wk. incubation 120 F. 2 wk. incubati 120 rere e rg lg Freshtest 50% relative humidity 50% relative fi midit g" based on Rel. Rel.Rel. Compound gelatin speed Gamma Fog speed Gamma Fog speed Gamma FogNone 100 1. 23 1e 76 1. 02 0. 43 4 Example 4-. 3 73 1. 03 11 a7 .87 0.12 52 I None 100 1. 42 .20 83 1. 21 0.38 21 73 1' 13 Example 5-. 1 e4 1.a5 .13 63 1. 05 0. 23 35 .83 '03 None 100 1. 3s .16 94 1. 39 0. 21 e0 121 36 Example 6-- 1 71 1. 23 11 1.00 0.15 47 1. 33 I18 form and asolution of 69 parts of potassium carbonate in Example 9 600 parts ofwater is stirred vigorously at reflux for 46 hours and filtered. Thechloroform layer is evaporated and the residue slurried first withethanol and then ether giving 13.6 parts of crude 2,2.-p-phenylenebis(S-dimethylaminoacrolein). The unreacted solid from thefiltration is treated further with aqueous carbonate to give anadditional 12.5 parts of product. Recrystallization from acetonitrileyields 22.5 parts of the pure dialdehyde; M.P. 211-- 213 C. A mixture of5.4 parts of 2,2'-p-phenylenebis(3- dimethylaminoacrolein), 3.1 parts ofhydroxylamine hyis employed in some compositions. The results obtainedare as follows:

TABLE 3 Percent Percent swell by weight Hardener of vehicle DK-6O FixWash Con 1, 400 600 700 Resorcinol diglyeidyl eth 490 170 170 Examp 3690 190 190 Control. 2, 300 850 960 Example 2 5 940 270 290 The aboveprocedure is repeated using a copolymer consisting of 90 percent butylacrylate by weight and percent acrylic acid by weight in place of the80/20 ethyl acrylate-acrylic acid copolymer. The swellingcharacteristics are given in the following table:

TABLE 4 Percent Percent swell by weight Hardener of vehicle DK-50 FixWash Example 3 190 83 83 Control- 250 150 150 Example 2 6 190 100 100Similarly good results are obtained using the hardeners of Examples 4,5, and 6 in similar ranges (percent by weight) as in the aboveprocedure.

Example 10 TABLE 5 Percent by weight of gelatin Percent swell HardenerExample 11 As already indicated, the hardeners employed in accordancewith our invention are particularly useful in photographic emulsions inwhich color couplers have been incorporated. In contrast to some priorart hardeners, it has been found that the hardeners described hereinresult in reduced stain with no significant adverse photographiceffects. Also no adverse effect upon dye hue or stability of theemulsion has been noted. To illustrate, two separate elements areprepared having the following layer arrangement. The use of the hardeneris varied between the two elements as described hereinafter.

Layer 6.Gelatin layer.

Layer 5.Red-sensiti-ve silver chlorobromide gelatin consisting of 90mole percent bromide plus a phenolic cyan coupler of the type describedin U.S. Pat, 2,423,730.

Layer 4.Gelatin layer plus an ultraviolet absorber.

Layer 3.--Green-sensitive silver chlorobromide gelatin emulsionconsisting of mole percent chloride plus a pyrazolone magenta coupler ofthe type described in U.S. Pat. 2,600,788.

Layer 2.--Gelatin layer.

Layer l.Blue-sensitive silver chlorobromide gelatin emulsion consistingof 98 mole percent bromide plus an acyl acetanilide yellow coupler ofthe type described in U.S. Pat. 2,875,057.

In one element mucochloric acid is the hardener used in all six layersin concentration of 0.54 percent by weight of gelatin and in the otherelement all six layers contain 1 percent by weight of the hardener ofExample 3. The above layers are coated on paper support in the ordergiven, layer 1 being immediately adjacent to the paper. Exposure of thetwo samples and processing by a color development process used in makingcolor prints indicates the improvement in stain in the case of hardenersin accordance with the invention as compared to an aldehyde typehardener as represented by mucochloric acid. The improvement in stain isshown by the increase in percent of reflectance, measured by a recordingspectrophotometer and compared with the sample in which thealdehyde-type hardener has been used.

The invention has been described in considerable detail with particularreference to certain preferred embodiments thereof, but it will beunderstood that variations and modifications can be effected within thespirit and scope of the invention as described hereinabove, and asdefined in the appended claims.

We claim:

1. A photographic element comprising a support, and a layer comprised ofa carboxyl-containing polymer hardened with a bis isoxazolitunquaternary salt comprising two isoxazole rings unsubstituted in their 3positions and linked at their 2, 4 or 5 positions through a divalentaliphatic or aromatic group.

2. A photographic element comprising a support, a photographic silverhalide, a color coupler, a carboxylcontaining polymer and a hisisoxazolium quaternary salt in hardening concentration, said saltcomprising two isoxazole rings unsubstituted in their 3 positions andlinked at their 2, 4 or 5 positions through a divalent aliphatic oraromatic group.

3. A composition comprising a hydrophilic colloid containing a hisisoxazolium quaternary salt in hardening concentration, said saltcomprising two isoxazole rings unsubstituted in their 3 positions andlinked at their 2, 4 or 5 positions through a divalent aliphatic oraromatic group.

4. A composition of claim 8 in which said hydrophilic colloid comprisesgelatin.

5. A composition of claim 8 in which said hydrophilic colloid comprisesgelatin and alkyl acrylate-acrylic acid copolymer.

6. A composition comprising a gelatin silver halide photographicemulsion comprising a his isoxazolium quaternary salt in a hardeningconcentration, said salt having the formulae:

9 10 where each Z is a divalent aliphatic or aromatic radical,References Cited $51151 iiiifiiri i 2%???222335 that; 32%;; a Y 1 0 to 2and each X is an anion, provided R is not linked 3316095 4/1967 VonCompen 96.400 to lsxazle the 3 5 NORMAN G. TORCHIN, Primary Examiner 7.A composition comprising a hardenable carboxylcontaining polymer and aquaternary salt in hardening FIGHTER, Assistant Examiner concentration,said salt comprising two isoxazole rings unsubstituted in their 3positions and linked at their 2, 4 or 5 positions through a divalentaliphatic or aromatic 10 10 .425; 2 7 group.

